Cement composition



lUti. COMPOSITIONS,

OATING OR PLASTIC Patented June 28, 1927.

UNITED sT-A Tss Cross Reference PATENT OFFICE;

ROBERT sn'rn LUDSTBOH, OI CKICAGO, ILLINOIS.

ORIENT OOIPOSI'II ON.

Io Drawing.

'5 pavements and t e like, or of concrete tanks iement that is ground or re-groun 25 and chutes or other such structures, the surfaces of which are apt to deteriorate upon exposure to wear. One of the chief objections to the use of concrete for floors, stairways, or other structures, the surfaces of which are exposed to attrition, is that such surfaces, particularly if subject to moisture, gradually wear and deteriorate and so give rise to considerable dust. Numerous attempts have been made to prevent disintegration of concrete surfaces exposed to wear and moistureb adding ingredients to the concrete mix or y coating the exposed surfaces, but none have been entirely satis factory. Y

I have found that a satisfactory non-dusting, wear and water roof coating or surfacing can be-formed rom standard Portland to a ieness such that at least 90 per cent will pass through a 200 mesh sieve andadmixed with from to per cent by weight, of an abrasive, such as carborundum, of a fineness to pass through a 100 mesh sieve.

l Only about 78 .per cent of standard Portland cement will pass a 200 mesh sieve and I deem it essential that it be re-round to very fine powder and such tre than about 10 per cent will remain on a 200 as mesh sieve. Such re-grinding develops the full efficiency of the cement and renders the finished concrete water and moisture-resisting or substantially waterproof and so aids in preventing the deterioration and wear of 40 the surface.

The re-ground cement is intimately and uniformly mixed with an abrasive such as carborundum or imp-flee corupdum of about IOU mesh fineness an in e propor-.

tion of from 5 to 10 lbs. of the abrasive to one cubic foot or 94 pounds of cement. The

abrasives specified have a specificgravity of.

3.1 or practically the same-as that of stan ard Portland cement, so that the mixture so will remain uniform when stored or shipped in dry powdered form and also later on when admixed with sand, or other'aggregate, and water and applied as a concrete top ing, coating or surfacing to a suitable ass.

Hence also, it will remain uniformly distributed in the neat cement that rises to and an;.nsssnmxmmlmllnaam: militants-ew Application fled Kay 81,

land cement groun 1924. Ma 10. nears; [OZ 5 C txamine:

forms the finishing surface of the concrete.

In use, the improved cement composition 1s admlxed with sand or other aggregate or free from impurities and the agpreyate is preferably raded in accordance W1 1 ullers formuhard sharp torpedo sand is preferably employed in the proportions of one cubic foot of the im roved cement mixture to one and one-hal cubic feet of sand. If desired, the concrete mix may be molded into tile or brick and subsequently laid preferably with the bed and joints of the same composition and mix.

In practice, it is found that the fine reground .Portland cement and the abrasive mutually protect each other and prevent the dlsintegration, wear and dusting of the concrete surface. In lace of the carborundum, other abrasives same degree of hardness as carborundum and substantially the specific gravity of cement may be employed, but the abrasive should be ractically free of iron compounds that disintegrate upon exposure to moisture.

Changes may be inade in the details set forthwithout departure from the essentials of the invention as defined in the claims 1 I claim as "my invention: v

1. A composition adapted, when admixed as described with sand or like aggregate and water, to form a water and wear-resisting, non-dusting, concrete 'surfacing, for floors, walks, and the like, comprising an intimate admixture in dry owdered form of Portto a fineness such that substantially 90 per cent will pass through a 200 mesh sieve, and from 5 to 10 per cent by weifiht of an iron free abrasive'of substantia y the hardness and specific gravity of carborundum and of about 100 mesh fineness, substantially as described.

2. A water and wear-resisting, nondust-- aving substantially the- 

